Metastasis is the process by which a cancer can spread from the primary site to other parts of the body, typically by entering the bloodstream. Different types of tumors show a preference for traveling to specific organs and tissue, such as circulating breast cancer cells are likely to take root in bones, lungs, and the brain. The prognosis for metastatic cancer (also called stage IV cancer) is generally poor, hence a technique that could detect these circulating tumor cells before they have a chance of forming new colonies of tumors in other parts of the body could greatly increase a patient's chance of survival.

Fortunately, science advances daily and researchers have discovered a new device that could detect these tumors before they metastasize. Recently, mechanical engineers at Worcester Polytechnic Institute (WPI) have developed a chip that could trap and identify metastatic cancer cells from a small amount of blood drawn from a cancer patient. This chip is designed by Balaji Panchapakesan, associate professor of mechanized engineering at Worcester Polytechnic Institute (WPI) and representative of the Tiny Systems Lab, together with the postdoctoral specialist Farhad Khosravi, the study was published in the journal Nanotechnology.

The device includes an array of tiny elements, individually measuring 3 millimeters across. Each element has a well at the bottom, which contain antibodies attached to carbon nanotubes. Each well holds a specific antibody that will bind selectively to one type of cancer cell based on the genetic markers located on the cell surface. The carbon nanotubes used in the device act as semiconductors. When a cancer cell binds to one of the attached antibodies it creates an electrical signature that can be detected. These signals can be used to identify which of the elements in the array have captured cancer cells. The individual arrays are then removed and taken to a lab, where the captured cells can be stained and identified under a microscope.

By seeding elements with an assortment of antibodies, the device could be set up to capture several different cancer cells types using a single blood sample. The researchers could fill a total of 170 wells using just under 0.3 fluid ounces (0.85 milliliter) of blood. Using this small sample, they could capture between 1-1000 cells per device with capture efficiency between 62-100%.

The study started by using two antibodies specific for two markers of metastatic breast cancer, EpCam and Her2, which were attached to the carbon nanotubes in the chip. When a blood sample had been "spiked" with cells expressing those markers, and was placed on the chip, the device was shown to reliably capture only the marked cells. This technique has some additional advantages over other liquid biopsy devices, such as being able to capture circulating tumor cells far more efficiently than microfluidic chips (in which cells must latch onto anchored antibodies as they pass by in a stream of moving liquid). The WPI device is also highly effective in separating cancer cells from other cells and dissolved materials in the blood through differential settling.

Although the initial tests with the chip have been focused on breast cancer, the device could be set to detect a wide range of cancers, including lung and pancreatic cancer. The engineers have also planned to develop another advanced device that could be used not only for follow-ups for patients with cancer, but in routine cancer screenings as well.

Imagine now going to the doctor for your yearly physical and having your blood drawn and that one blood sample can be tested for a comprehensive array of cancer cell markers. Cancers would be caught at their earliest stage as well as other stages of development, and doctors would have the necessary protein or genetic information from these captured cells to customize your treatment based on the specific markers for your cancer.


COPYRIGHT: This article is property of We Speak Science, a non profit institution co-fonded by Dr. Detina Zalli (Harvard University) and Dr. Argita Zalli (Imperial College London). The article is written by Detina Zalli and Brisilda Pashaj (Plovdivski Universitet Paisii Hilendarski, Bulgaria ( Msc. Medical Biology).



FarhadKhosravi et al. Static micro-array isolation, dynamic time series classification, capture and enumeration of spiked breast cancer cells in blood: the nanotube–CTC chip, Nanotechnology (2016).